Macedonia was given a blunt warning by the European Union last night to seek a political solution to its problems with Albanian rebels or forego aid from Brussels.

Meeting after another shaky ceasefire was imposed by their foreign policy representative, Javier Solana, EU governments insisted that there was no military solution to the crisis, and urged Skopje to resume negotiations.

But they underlined their determination to stick to efforts to contain the latest Balkan flare-up by appointing François Leotard, a former French defence minister, their permanent envoy to Macedonia.

Britain announced that Jack Straw, the new foreign secretary, will visit Skopje for two days today.

"There is no military solution to the present crisis," said a communique issued after talks in Luxembourg. "The political dialogue must now resume with the facilitation of the international community and lead to rapid results.

"Such results will determine the further development of the EU's relations with the former Yugoslav republic of Macedonia and the possibility of further assistance."

Ministers expressed "concern" about the build-up of arms in a volatile region which has been teetering on the edge of civil war for more than three months.

The thinly veiled threat to cut off up to 90m euros (£55m) in aid is the strongest sign yet that the EU is losing patience after the repeated failure of diplomatic efforts.

In April the country was given a tailor-made "stabilisation and association" agreement with the union to encourage it to seek a peaceful solution to the conflict with the ethnic Albanian minority.

"We would like to support confidence-building measures, but it is difficult to build people's confidence when money, which is very clearly in short supply, is being spent on bombs and rockets," Chris Patten, the external relations commis sioner, said yesterday. "There is little we can do in terms of financial support until there is a political settlement."

Nato announced last week that it was ready to send in several thousand men as a "disarmament force" but only once a durable ceasefire and political process was in place. It called the weekend attack on rebel positions "madness".

Spokesmen in Luxembourg for the rebel force, the National Liberation Army, insisted that Nato still had an important role to play, underlining their will for international intervention.

Macedonia's foreign minister, Ilinka Mitreva, was told by EU colleagues in "frank" talks that they were disappointed by the failure to make progress in negotiations on constitutional change by yesterday's deadline.

the German foreign minister, Joschka Fischer, said the EU needed a more permanent representation in Skopje - in the form of Mr Leotard and the former French justice minister Robert Badinter - to push Macedonia to reconciliation and ensure its independence.

"It is in our interest that Macedonia's territorial integrity remains intact," he said.